Cardiac Myxoid Spindle Cell Tumor in a Neonate

A report describes a case of a male neonate, born vaginally at a gestational age of 39 weeks with an Apgar score of 9 to 10 and a weight of 3480 grams. He suffered progressive respiratory distress that required intubation and surfactant administration. His blood culture was positive for coagulase-negative staphylococci. 

Initially, the patient received a diagnosis of respiratory distress and sepsis and was planned for antibiotherapy, total parenteral nutrition, sildenafil, and ibuprofen. However, Echocardiography at birth showed mild tricuspid regurgitation (TR), small atrial septal defect (ASD), and patent ductus arteriosus (PDA). Further echocardiography assessment showed evidence of mild right atrium (RA) enlargement with a heterogeneous rounded mass lesion (1.72 ✕ 1.95 cm) within the RA cavity, a left ventricular (LV) ejection fraction of 50%, moderate TR, mild mitral regurgitation (MR), PDA (2.6 mm), and normal right ventricular (RV) function. The presence of a mass indicated the possibility of atrial myxoma. Hence, the patient was scheduled for surgical resection. 

Sternotomy and total thymectomy were carried out. After cannulating the aorta, inferior vena cava (IVC), and superior vena cava (SVC), cardiopulmonary bypass (CPB) was initiated, and IVC and SVC were snared. The PDA was shut from inside the main pulmonary artery (MPA), the MPA was repaired, the aorta was clamped, cardiac arrest was induced, and the RA was opened. A firm mass located in the lateral atrial wall extending to the IVC and anterior to it was widely resected (2 ✕ 2 cm) with a safe margin up to the edge of the suprahepatic veins. It was then repaired using an autologous pericardial patch, de-aired, and the aortic clamp was removed. After rewarming, the patient was disconnected from the CPB and transferred to the ICU with stable vital signs.

Considering the intraoperative and postresection evaluation of the tumor, the radiologic size, and macroscopic features, the definite diagnosis of RA myxoid spindle cell tumor was made, and the patient was discharged in good clinical condition.

Follow-up echocardiography after 1.5 years showed no RA mass, mild TR, normal size RA, mild left atrial enlargement, no residual PDA, tricuspid annular plane systolic excursion of 12 mm, and normal LV function. At the three-year follow-up, ultrasound and CT scan of the abdomen and pelvis were free of any evidence of malignant involvement or extracardiac manifestations related to metastasis, thus confirming the benign nature of the lesion.

Abbaszadeh R, Naderi F, Jalali AH, et al. Cardiac Myxoid Spindle Cell Tumor in a Neonate. Case Reports in Pediatrics. 2024(1): 8630268. https://doi.org/10.1155/2024/8630268